30 minutes of exercise a day could counter risks of prolonged sitting
The recommendation is part of the WHO’s new global guidelines on physical activity and sedentary behaviour.
Exceeding weekly recommended physical activity levels could offset the health harms caused by prolonged sitting, the World Heath Organisation (WHO) has said.
Its recommendation, published in a special issue of the British Journal of Sports Medicine, is part of the new global guidelines on physical activity and sedentary behaviour. In addition, new research, also published in the special issue, has suggested that increasing physical activity can counter the risk of early death linked to long periods of sedentary time.
“Although the new guidelines reflect the best available science, there are still some gaps in our knowledge," said Professor Emmanuel Stamatakis, of the University of Sydney, who is the co-editor of the special issue.
“We are still not clear, for example, where exactly the bar for ‘too much sitting’ is. But this is a fast-paced field of research, and we will hopefully have answers in a few years’ time.”
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He added: “These guidelines are very timely, given that we are in the middle of a global pandemic, which has confined people indoors for long periods and encouraged an increase in sedentary behaviour. But people can still protect their health and offset the harmful effects of physical inactivity.
“As these guidelines emphasise, all physical activity counts and any amount of it is better than none. There are plenty of indoor options that don’t need a lot of space or equipment, such as climbing the stairs, active play with children or pets, dancing, or online yoga or Pilates classes.”
In research involving more than 44,000 people from four countries, scientists have found a high daily tally of sedentary time – defined in the study as 10 or more hours – to be associated with “a significantly heightened risk of death, particularly among people who are physically inactive”.
The researchers said that 30 to 40 minutes of moderate to vigorous intensity physical activity a day “substantially weakens this risk, bringing it down to levels associated with very low amounts of sedentary time”.
The authors also said the findings broadly confirm the recommendations set out in the WHO’s global guidelines on physical activity and sedentary behaviour.
But, they added, there is not enough evidence to recommend specific maximum thresholds for sedentary behaviour.
The WHO guidance recommends a weekly tally of 150-300 minutes of moderate intensity, or at least 75-100 minutes of vigorous intensity.
But any amount of physical activity is better for health than none, it emphasises.
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Other key recommendations for adults, including those living with long-term conditions or disabilities at any age, also include undertaking muscle-strengthening activity – such as weights, core conditioning – at moderate or greater intensity on two or more days of the week.
The guidance also says that adults aged 65 and over should do physical activity that emphasises functional balance and strength training at moderate or greater intensity on three or more days of the week, in order to enhance functional capacity and prevent falls.
It recommends that women should do regular physical activity throughout pregnancy and after the birth, to include various aerobic and muscle-strengthening activities.
Is my chair killing me?Sixty years ago, researchers found that bus drivers had twice as many heart attacks as bus conductors. The difference was that the conductor was on his feet all day, whereas the driver was sitting down.
Nowadays, adults in the UK commonly spend seven or more hours a day sitting down, and this tends to increase as people get older. Long periods of sitting are typically associated with an inactive lifestyle, which is a risk factor for heart disease, dementia and diabetes.
It’s a vicious cycle because the collagen around your tendons and ligaments tends to harden when the joints aren’t moving, and the postural muscles around your trunk gradually get weaker. This reduces your flexibility and makes you more likely to strain your back or shoulders when you bend or lift. Without the need to support your weight, your leg bones become more porous and blood tends to pool in your ankles, which can lead to varicose veins and even deep vein thrombosis (dangerous blood clots in your veins).
The good news is that a 2016 analysis of studies of over a million people found that you can completely counter the negative effects of a desk job by doing 60 to 75 minutes of moderate physical exercise every day. Standing or walking during meetings and standing while talking on the phone are both good ways to start reducing your daily sitting time.